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Eyewitness Testimony

The Facts

Is It Reliable?

People usually assume that memory is like a video camera - it records perfectly what you see and experience in an event - that even if you forget things, the facts you remember are correct

However, even very basic cognitive psychology can tell you that only 20% of what you see/hear is actually transferred even to your short term memory

Furthermore, recall is dependant upon circumstances at the time (Cue-Dependant Recall Theory)

If giving evidence in court or in a police station, the location (context) is different, and also probably their mental state (seeing a crime is much more stressful than giving evidence), and so they will be less able to recall

Therefore, when recalling events, your brain has very little material to work with, and constructs its account based on its pre-existing experience (schemas)

Furthermore, Clifford and Hollin (1981) showed that violent events are recalled worse

In 1974 she (and others) found that the smallest changes in how a question is phrased had a large effect on the answer given - a kind of experimenter effect

(This is coming up again later!)

The Psychology - Applied!

The Cognitive Interview

Subjects are interviewed as soon as possible - Malpass and Devine (1981) found that after 3 days, no false identifications were made, but after 5 months, 35% of identifications were false

The questions are open, in an attempt to avoid leading questions and hence avoid "corrupting" the witness' memory

(Loftus again!)

The witness is encouraged to report every aspect of the incident, and then to try and think about how others may have viewed it

The cognitive interview is closely linked to...

Identity Parades

It's hard to think of a more convincing piece of evidence than a person being picked out of a line and identified by a witness - entire court cases can be built on them

As recall changes based on the way a question is asked, and these are so important, clearly police must be careful during identity parades!

If you asked:

"Which of these people commited the crime?"

You are much more likely to get an identification than if you asked:

"Was it one of these people the one who commited the crime?"

But the identification could VERY easily be false!

Evaluation!

These techniques are all based in solid cognitive psychology theory, as opposed to 'traditional' police methods, which come from the dark times of PF (pre-Freud)

Geiselman (1984) found that the cognitive interview gives up to 35% more information than a standard interview

The BUTs!

The act of attempting to imagine what someone else saw can corrupt the memory

These techniques are obviously time consuming, and many police officers may not have the time (or training) to carry it out properly

Furthermore, it's one thing for a psychologist in a lab to come up with theories - but what right does he have to tell the police how to do their jobs?

But psychology can help!

There is more to eyewitness testimony that meets the eye (sorry, couldn't help it)

Your memory is far from perfect

This field of psychology benefits society through the improvement of the legal system.

By increasing the reliability of EWT (TLA there), criminals will be caught more, and innocent people convicted less

Failed/false convictions are highly costly, both financially and in terms of the "human factor"

I could quote statistics on how many people are falsely convicted of crimes...

But that wouldn't mean anything to you

So alongside the benefits to society, think of the human side - what it would be like to spend half your life in jail for a crime you didn't commit

Psychology can help that situation be avoided

Surely that's a pretty big benefit?

Therefore, reconstructions of the scene should help significantly with recall

Basic cognitive psychology studies into memory (Godden and Baddeley anyone?) show that recall is substantially better when in the same enviroment as when the event (learning) took place

Reconstructions

However, it is possible that the witness may get the real event and the reconstruction 'mixed up', damaging their later testimonies ("post-event information")

What is it?

Giving evidence in court about (usually) a crime

Juries give a lot of weight to witnesses

They can sway the result of a trial!

Do we need it?

Therefore, it is important to the legal system, and by extension, society, that their testimony is as accurate as possible

BUT - trials are changing due to forensic evidence and how the jury perceives it - the CSI effect!

However, recently serious doubts have been raised about the quality of this evidence - whilst it has high positive rate, it also has a high negative rate - it isn't good at pointing out that someone HASN'T done something

Therefore, eye witness testimony is still very necessary - and in the face of forensic evidence, proving/improving its reliability is just as important as ever!

Obviously, this will affect testimony of crimes

Atkinson and Shiffrin, 1968, MSM

Bartlett 1932

Tulving 1974

Elizabeth Loftus has done a lot of research into this field

And they're big buts! ;)

And so:

And I couldn't find any...

MJB 6C1

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